MOLECULAR PHYLOGENY OF EUKARYOTES

这项建议是关于系统起源的。有核的细胞在哪里？ 来自什么，分子和超微结构创新是什么 允许它们形成吗？谁是高等生物的微生物祖先 植物、动物和真菌王国？什么是分类界限？ 区分真核生物的主要群体以及它们之间的相互关系？这个 答案就在普罗提斯塔王国，它的成员统治着 真核生物的进化史。最早的有核细胞和 植物、动物和真菌的最后共同祖先是原生生物，但 这个分类群不是一个紧密的进化组合。相反， 它描述了组织的层级，用形而上学来表示 不能被确定地归入系统发育中的血统 语境采用传统的比较形态、生理学方法 或者是生物化学。分子系统学提供了一个新的机会 建立客观的、定量的系统发展图；可使用的框架 为了解释发散分类群中的分子和结构相似性， 确定自由活着的亲属，以保护人类寄生虫，并设计 用于病原体鉴定的诊断rRNA探针。在过去 几年来，对核糖体RNA编码区的比较 彻底改变了我们对真核生物进化的看法。而不是三个 “高等王国”，有五大复杂的进化组合 这几乎同时且相对较晚地出现在 真核生物血统的进化史。大块头 类系辐射之前有独立原生生物的进化。 血统；有些与古细菌和真细菌系一样古老 下降。最早的分支由线粒体代表 寄生虫，其中许多寄生虫会导致人类疾病。然而，信息 关于真核生物最深层的分支模式是最小的，而不是 但仍有可能确定主要真核生物的分离顺序 组。这项提议目标是构建一个量化的 基于小分子比较的真核生物系统发育框架 亚单位核糖体RNA基因序列。

This proposal is about phylogenetic origins. Where did cells with nuclei come from and what are the molecular and ultrastructure innovations that permitted their formation? Who were the microbial ancestors to the higher kingdoms of plants, animals and fungi? What are the taxonomic boundaries separating major groups of eukaryotes and how are they interrelated? The answers lie within the kingdom Protista whose members dominated the evolutionary history of eukaryotes. The earliest cells with nuclei and the last common ancestor to plants, animals and fungi were protists, but this taxonomic group is not a cohesive evolutionary assemblage. Instead, it describes levels of organization and is represented by paraphyletic lines of descent that can not be definitively placed in a phylogenetic context using traditional methods of comparative morphology, physiology or biochemistry. Molecular systematics offer a new opportunity to assemble objective, quantitative phylogenies; frameworks that can be used to interpret molecular and structural similarities in divergent taxa, to identify free living relatives to obligate human parasites, and to design diagnostic rRNA probes for identification of pathogens. During the past few years, comparisons of ribosomal RNA coding regions have revolutionized our perspective on eukaryotic evolution. Instead of three "higher kingdoms", there are five major complex evolutionary assemblages that diverged nearly simultaneously and relatively late in the evolutionary history of the eukaryotic line of descent. The massive phyletic radiation was preceded by a progression of independent protist lineages; some as ancient as the archaebacterial and eubacterial lines of descent. The earliest branches are represented by amitochondrial parasites, many of which cause disease in humans. However information about the deepest eukaryotic branching patterns is minimal and it is not yet possible to identify the order of separation for the major eukaryotic groups. The goal of this proposal is construct a quantitative phylogenetic framework for eukaryotes based upon comparisons of small subunit ribosomal RNA gene sequences.